I'm using Ubuntu as the only operating system since two years. In the first Ubuntu versions I had seen my BIOS screen and the boot screens. Actually im using Ubuntu 12.04 and my screen stays black until Ubuntu is started (both screens are missing). I guess this situation appeared the first time in Ubuntu 11 (not sure).

I searched via google and tried the popular activities but was not able to fix my issue. I opened the laptop and checked all connections. I'm using boot option nomodeset. I had a look through many many web pages. I don't know how to continue and hope somebody could be helpful.

My hardware:
Acer Aspire 9300
AMD Turion 64 x2 NVIDIA GeForce Go 7600 (using proposed driver)

lspci | grep NVIDIA
00:00.0 RAM memory: NVIDIA Corporation C51 Host Bridge (rev a2)
00:00.1 RAM memory: NVIDIA Corporation C51 Memory Controller 0 (rev a2)
00:00.2 RAM memory: NVIDIA Corporation C51 Memory Controller 1 (rev a2)
00:00.3 RAM memory: NVIDIA Corporation C51 Memory Controller 5 (rev a2)
00:00.4 RAM memory: NVIDIA Corporation C51 Memory Controller 4 (rev a2)
00:00.5 RAM memory: NVIDIA Corporation C51 Host Bridge (rev a2)
00:00.6 RAM memory: NVIDIA Corporation C51 Memory Controller 3 (rev a2)
00:00.7 RAM memory: NVIDIA Corporation C51 Memory Controller 2 (rev a2)
00:02.0 PCI bridge: NVIDIA Corporation C51 PCI Express Bridge (rev a1)
00:03.0 PCI bridge: NVIDIA Corporation C51 PCI Express Bridge (rev a1)
00:04.0 PCI bridge: NVIDIA Corporation C51 PCI Express Bridge (rev a1)
00:09.0 RAM memory: NVIDIA Corporation MCP51 Host Bridge (rev a2)
00:0a.0 ISA bridge: NVIDIA Corporation MCP51 LPC Bridge (rev a3)
00:0a.1 SMBus: NVIDIA Corporation MCP51 SMBus (rev a3)
00:0a.3 Co-processor: NVIDIA Corporation MCP51 PMU (rev a3)
00:0b.0 USB controller: NVIDIA Corporation MCP51 USB Controller (rev a3)
00:0b.1 USB controller: NVIDIA Corporation MCP51 USB Controller (rev a3)
00:0d.0 IDE interface: NVIDIA Corporation MCP51 IDE (rev f1)
00:0e.0 IDE interface: NVIDIA Corporation MCP51 Serial ATA Controller (rev f1)
00:10.0 PCI bridge: NVIDIA Corporation MCP51 PCI Bridge (rev a2)
00:10.1 Audio device: NVIDIA Corporation MCP51 High Definition Audio (rev a2)
00:14.0 Bridge: NVIDIA Corporation MCP51 Ethernet Controller (rev a3)
03:00.0 VGA compatible controller: NVIDIA Corporation G73 [GeForce Go 7600] (rev a1)

So my question is what to do to fix the black screen during boot?